The BIG project thread

Show off your work! Anything from final results to full start-to-finish project journals.



Top Contributor
Posts: 3040
Joined: Tue Sep 16, 2008 1:17 pm
Location: Pahrump NV.
Country:
USA
PostPosted: Mon Apr 09, 2012 1:27 am
Just my opinion but I think the support on that crank is a very bad idea.

The crank shaft isnt desighnd to take the weight better to let the engine sag on the light weight engine stand it will bow and sag but it will support the weight.

My point is a crank shaft will bend very easily more easily than most guys think too.
Most guys think that to straiten a crank shaft you need to use a press or Machine turn it strait the truth is REAL crank shaft straitning is done with a hammer on V blocks with a dial indicator.

Also never Lay a crank down on its side always stand them up or hang them they will bend easily.
You cant see it looking at it you have too put it in the block or V blocks and check the run out at each Main.
Usually if its within .002" I dont get too excited of course your looking for less than .002 but its hard to get one that strait and keep it strait especialy if you have to transport it from machine shop to home.

But supporting the engine on the front throw deffinatly a no no
Those who sacrifice liberty for security deserve neither

User avatar

Top Contributor
Posts: 4274
Joined: Thu Jan 06, 2005 12:15 pm
Location: Canada
PostPosted: Mon Apr 09, 2012 10:11 am
Well I hope it doesn't end being a problem :flatten: :flatten:

It's a really heavy engine so the fear was it was going to break the stand and come crashing down. It's too late now so I'll find out soon enough.
Rob



Top Contributor
Posts: 3040
Joined: Tue Sep 16, 2008 1:17 pm
Location: Pahrump NV.
Country:
USA
PostPosted: Tue Apr 10, 2012 10:24 am
Rob
I would check it out if I were to buy that engine from you just to make sure If I were to come buy the engine from you if it were for sale just to be safe. no harm no fowl till it gets started and its out of whack.
All the bearings and gaskets are reusable at this point unless they were glued down on both sides.
Just too easy to check Right now and a much cheaper mistake right now before it gets in the car and started.

What was the RUN OUT when You first installed just the crank?

I have seen and witnessed cranks being bent from guys hammering on Harmonic balancers till they can get the bolt in too pull it down, Then they wonder why the front main lets go. They make Harmonic balancer install tools for a reason.

The idea of the engine being being built and turned upside down while being supported on the crank like that scares me.
I would tear it down and recheck but I am a certified aircraft engine builder too I always error on the side of safty and reliability.

Better safe than sorry :goodjob:
Those who sacrifice liberty for security deserve neither

User avatar

Top Contributor
Posts: 3107
Joined: Wed Dec 01, 2010 10:52 pm

Country:
USA
PostPosted: Tue Apr 10, 2012 11:00 am
Dennis, I can appreciate your opinion and understand your point of view...especially on storing cranks on their end. I never thought about the part of rotating the engine with that brace intact. Cranks will flex/bend a certain amount (depending on their makeup cast being more) before taking a bad set. I was thinking no harm in a little support considering in use you look at say....400 plus ft lbs torque with explosions behind it 1000's of times a minute vs sitting on a stand merely supporting it. You are right by erring to the safe/good/reliable side. I have never installed a crank with more than .0005 run out. I got it right on decimals....half of a thousandth. I used a straightening machine, press type, with indicator to straighten cranks when I first started doing that in the early 80's (lost count) until an old man showed me the best way to do it...as you said with a sledge hammer (lost count on that too)...LOL! Days long past I no longer miss... Have a great week guys!
Never argue with an idiot, he will drag you down to his level and beat you with experience.

User avatar

Top Contributor
Posts: 4274
Joined: Thu Jan 06, 2005 12:15 pm
Location: Canada
PostPosted: Tue Apr 10, 2012 12:02 pm
I'll have a chat with the builder and see what he thinks. I have no idea if it was built with the support arm on or if that was put on after when the heads, intake, etc. went on or how long it was on for that matter. The motor is off the stand altogether now, waiting to go in.
Rob



No Turning Back
Posts: 957
Joined: Tue Mar 09, 2004 4:19 pm
Location: Cowan Heights Ca
PostPosted: Tue Apr 10, 2012 3:36 pm
Boy I really don't know. This is all great advise. :goodjob: :goodjob: With my very novice thought, :whoops: :whoops: I wouldn't think that support was holding more weight than a tight set of fan belts would would apply. Rob, was that support holding allot of weight or merely a safety brace in case things let go? Anyway I felt a need to express an opinion based on nothing more than my logic and worth about as much . . . but I feel better now :happy: :happy: . Now if it were in a plane and my life depended on it I am with you Dennis even though that old Buick would be one heck of a heavy power source :rotfl: :rotfl:
it needs to be lowered with big and littles. .

User avatar

Top Contributor
Posts: 3107
Joined: Wed Dec 01, 2010 10:52 pm

Country:
USA
PostPosted: Tue Apr 10, 2012 3:38 pm
LOL!

:allgood: :rotfl: :rotfl:
Never argue with an idiot, he will drag you down to his level and beat you with experience.

User avatar

Top Contributor
Posts: 4274
Joined: Thu Jan 06, 2005 12:15 pm
Location: Canada
PostPosted: Tue Apr 10, 2012 4:37 pm
Doug's 38 2dr sedan wrote:was that support holding allot of weight or merely a safety brace in case things let go?


Well, um, I didn't try to lift it but I would say a fair bit of weight for sure. :knockout: :knockout: These nailheads are extremely heavy. I too would like to think that a bit of weight on the end wouldn't amount to more than whatever load would go on it in use but then I'm utterly clueless. :splat:
Rob



Top Contributor
Posts: 3040
Joined: Tue Sep 16, 2008 1:17 pm
Location: Pahrump NV.
Country:
USA
PostPosted: Tue Apr 10, 2012 4:48 pm
http://www.youtube.com/watch?v=S9Z6hK4pzzc

http://www.youtube.com/watch?v=OULR4FoB ... re=related

http://www.youtube.com/watch?v=HI8v-OG_ ... re=related

You guys do what you want I know better
Those who sacrifice liberty for security deserve neither

User avatar

Top Contributor
Posts: 3107
Joined: Wed Dec 01, 2010 10:52 pm

Country:
USA
PostPosted: Tue Apr 10, 2012 5:27 pm
Thanks dennis I try. :goodpost:

.0005 for me but I am not a Harley mechanic. Is that why they vibrate so bad?
Never argue with an idiot, he will drag you down to his level and beat you with experience.
PreviousNext

Return to Completed & In Progress Member Projects

Who is online

Users browsing this forum: Yahoo [Bot] and 10 guests